(FACT-2858) Added acceptance test for migrating from facter 3 (#2199)

acceptance/tests/options/config_file/cache_migrate_from_facter_3.rb

@@ -0,0 +1,86 @@
+test_name 'migrating from facter 3 to facter 4 having cache enabled' do
+  tag 'risk:high'
+
+  require 'facter/acceptance/user_fact_utils'
+  extend Facter::Acceptance::UserFactUtils
+
+  fact_group_name = 'uptime'
+  config_data = <<~FACTER_CONF
+    facts : {
+      ttls : [
+          { "#{fact_group_name}" : 3 days }
+
+      ]
+    }
+  FACTER_CONF
+
+  f3_cache =
+    "{
+      \"system_uptime\": {
+        \"days\": 1,
+        \"hours\": 1,
+        \"seconds\": 1,
+        \"uptime\": \"1 day\"
+      },
+      \"uptime\": \"1 days\",
+      \"uptime_days\": 1,
+      \"uptime_hours\": 1,
+      \"uptime_seconds\": 1
+    }"
+
+  agents.each do |agent|
+    cache_dir = get_cached_facts_dir(agent['platform'], on(agent, facter('kernelmajversion')).stdout.chomp.to_f)
+    f3_cache_file = File.join(cache_dir, fact_group_name)
+
+    config_dir = get_default_fact_dir(agent['platform'], on(agent, facter('kernelmajversion')).stdout.chomp.to_f)
+    config_file = File.join(config_dir, 'facter.conf')
+
+    step 'create cache file' do
+      agent.mkdir_p(cache_dir)
+      create_remote_file(agent, f3_cache_file, f3_cache)
+    end
+
+    teardown do
+      agent.rm_rf("#{cache_dir}/*")
+      agent.rm_rf(config_file)
+    end
+
+    step 'calling facter 4 without config won\'t modify the cache file' do
+      _output = on(agent, facter)
+      stdout = agent.cat("#{cache_dir}/#{fact_group_name}")
+
+      assert_equal(stdout.strip, f3_cache.strip)
+    end
+
+    step "Agent #{agent}: create config file" do
+      agent.mkdir_p(config_dir)
+      create_remote_file(agent, config_file, config_data)
+    end
+
+    step 'calling facter will invalidate old f3 cache and will overwrite' do
+      output = on(agent, facter('--json'))
+
+      step 'output should be different from f3 cache' do
+        parsed_output = JSON.parse(output.stdout)
+
+        cache_value_changed = f3_cache['system_uptime']['seconds'] != parsed_output['system_uptime']['seconds']
+        assert_equal(true, cache_value_changed, 'Cache value did not change')
+      end
+
+      step 'cache file should contain cache_format_version' do
+        stdout = agent.cat("#{cache_dir}/#{fact_group_name}")
+        cache_content = JSON.parse(stdout)
+
+        assert_equal(cache_content['cache_format_version'], 1)
+
+        step 'values should be read from cache' do
+          cached_value = cache_content['system_uptime.seconds']
+          sleep 1
+          output = on(agent, facter('system_uptime.seconds'))
+
+          assert_equal(cached_value.to_s, output.stdout.strip)
+        end
+      end
+    end
+  end
+end